Selector circuits are typically utilized in a power supply block for various electronic devices. Such selector circuits are generally designed to select between a DC power source, e.g., an AC/DC adapter, and a rechargeable battery. In various electronic devices like a laptop computer, such selector circuits are typically controlled via control signals communicated via a System Management Bus (SMBus) according to a specified protocol. In addition, such selector circuits typically cannot independently ascertain, correct, and notify other components in the power supply block of a power crises condition. In addition, such selector circuits are not configured to accept control signals from an associated host power management unit.
Charging circuits are typically utilized to regulate battery charging conditions when a selector circuit has selected one or more batteries for charging. Most charging circuits for use with multiple batteries do not permit charging multiple batteries in parallel. For those charging circuits that do permit charging of multiple batteries, only the total battery charging current is controlled and maintained below a maximum limit. Hence, battery charging time is increased. For example, if two similar batteries were to be charged in parallel in such an instance, the average charging current per battery would only be half of the maximum permitted even if the maximum power level from the associated DC power source (e.g., an AC/DC adapter) is not reached. Accordingly, there is also a need in the art for a charging circuit with enhanced parallel charging capabilities.